JPS62136242A - Uranium adsorbent - Google Patents

Abstract

PURPOSE:To make it possible to effectively recover uranium in seawater or waste water by adsorption, by using a calyxarene derivative. CONSTITUTION:A calyxarene derivative represented by formula (wherein M is hydrogen or a metal ion, R is hydrogen, a lower alkyl group or lower alkyl carboxylic acid, x and y are hydrogen or an alkyl and n is an integer) is obtained by a method wherein p-tert-butyl calyx [n] allene is debutylated in toluene using anhydrous aluminum chloride to obtain calyx [n] allene and conc. sulfuric acid is added thereto to perform heating. When n in the formula is 4-10, said derivative is water-soluble and has a cavity just good for collecting an uranyl ion. The uranyl ion has a pseudo-plane hexadentate structure in seawater unlike the other metal ion and the aforementioned calyxarene derivative has extremely excellent selectivity in the adsorption of uranium and large adsorbing power.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a novel uranium adsorbent.

(Conventional technology) Nuclear power, hydropower, wind power, tidal power, and other energy sources are being considered as alternatives to oil, but none are superior to nuclear power in terms of technological perfection, cost, output, etc. do not have.

On the other hand, onshore reserves of uranium, which is used as fuel for nuclear energy, are estimated at 6 million tons, but this is not enough to meet future demand. However, in seawater,
The concentration of uranium is extremely dilute, only a few ppb, but a huge amount of uranium exists, totaling 4.2 billion tons. Although the technology for recovering uranium from seawater is being actively studied as an extremely important technology, a sufficient adsorbent has not yet been found.

Requirements for a uranium adsorbent include a large association constant with uranium and excellent selective adsorption of uranium to other metal ions.

Many uranium adsorbents have been proposed so far, and the representative ones include potassium titanate, amidoxime resin, and crown ether compounds, but they do not satisfy the above-mentioned requirements and are expensive. , adsorbent regeneration/
There were problems in terms of reusability, handling, etc. Also, the report by Zinke et al. in 1941 (Ber, dts
ch, Chem, Ges,.

Cornf 4 1729 (1941))
orth et al. (Brlt, J, Pharmacol
, , 107 B (1955) ) , , Kamme
(Makromol, Chem.

162 179 (1972)), Munch (Ma
kromol.

Chem, 178, 69 (1977))
and Gutsche et al. (J, Am, Chem, S.
oc, 1088782 (1981)) etc., the synthesis of various calixarene derivatives, which are cylindrical compounds consisting of a benzene ring, has been described.

However, all of the obtained calixsalene derivatives have the problem that they are not water soluble or have poor water solubility (
Of course, there is no mention of uranium adsorption from seawater).

(Problems to be Solved by the Invention) The present inventors have fully investigated the shortcomings of the prior art and conducted a thorough analysis of the existence form of uranium in seawater, and have completed the present invention. Ta. That is, uranium in seawater is
It exists stably in the form of a complex called O2(COs)s, and the uranyl ion tyo2 coordination structure has a pseudo-planar hexacoordination structure, which is similar to the planar four-coordination structure of other metal ions and This is significantly different from the tetrahedral structure. By utilizing this fact, it becomes possible to produce a uranium adsorbent with excellent selectivity and association constant for uranium.

An object of the present invention is to propose a uranium adsorbent having a completely new structure not found in conventional uranium adsorbents, and having excellent selective adsorption properties and water solubility.

(Means for Solving the Problems) The present invention is a uranium adsorbent made of a calixarene derivative represented by the following formula (I).

However, n: 4 to 10 M: hydrogen, ammonium ion, lower alkyl ammonium ion, metal ion R: hydrogen, lower alkyl group, lower alkyl carboxylic acid or salt thereof, unsaturated alkyl group or aromatic hydrocarbon x+ Y' Hydrogen, alkyl groups, aromatic hydrocarbons.

In the uranium adsorbent of the present invention, it is important that the kalikylene derivative represented by the above formula (I) has water solubility and has a cavity suitable for trapping uranyl ions (UO2). Therefore, in formula C11, n
is in the range of 4 to 1O, and if n is less than 3, synthesis is extremely difficult and the uranium adsorption property is poor, making it unusable. In addition, when n exceeds 10, it is difficult to synthesize, and even in calixsalene derivatives, which are cyclic compounds with a rigid unit called phenylmethyl group, flexibility in an aqueous solution increases,
2+ The adsorption selectivity for UO2 decreases and it cannot be used.

Further, M in the above (I1 formula 1) is a counter ion of S08, and includes hydrogen, ammonium ion, lower alkyl ammonium ion, metal ion, etc., and hydrogen or metal ion is preferable.

R is hydrogen, a lower alkyl group, a lower alkyl carboxylic acid or a salt thereof, an unsaturated alkyl group, or an aromatic hydrocarbon. Relatively short functional groups such as , hydrogen, methyl group, and carboxymethyl group are preferred. In particular, carboxymethyl groups have excellent selectivity and adsorption properties.

For x and y, use the above (OR and SO in the IJ formula)
Depending on the strength of hydrophilicity of aM and the number of n, there is no particular limitation as long as there is no deterioration in the water solubility of the calixarene derivative, its performance as a uranium adsorbent, etc. As n becomes larger, the annular groove structure also becomes larger, and rotation at -CH2- becomes easier1. Therefore, the calix [n
It is also possible to observe changes in the steric configuration of l-arene derivatives, but when n is less than 6 and R=H, the effect of water due to OH is strong, and OR<or SOBM) is directed in a certain direction. The probability of the structure (“cone” structure) is high. Also, R
is not hydrogen or n≧6, the solvent and the calix [
It is also necessary to consider the interaction with nl arene derivatives, but the cone structure is not necessarily required, and the OR (or 508
A structure in which the orientation of M) is alternated ("alterat
e” structure) is also included.The host-guest type complex formation reaction between UO2 and calix [nl arene derivatives] is also included.
When R is a lower alkyl carboxylic acid, coordination of eight carboxylates of calix arene is sufficient, and it becomes a good uranium adsorbent regardless of the above-mentioned conformity rule. If the substituent is co
The ne structure is preferable.

Next, an example of the method for manufacturing the uranium adsorbent of the present invention will be described to explain the present invention in more detail.

The starting materials in the method for producing the uranium adsorbent of the present invention are calix [nl arene and concentrated sulfuric acid.

Calix [nl Allen, e.g. C, D, Guts
che (Accounts of Chemical
Re5search, 198 B (16) 161~
It can be prepared by debutylating p-tert-butyl calix [nl arene prepared by the method of 170) in toluene using a dealkylating agent such as anhydrous aluminum chloride.

In a flask equipped with a reflux condenser, add 10 to 150 ml of concentrated sulfuric acid, preferably 40 to 100 ml of concentrated sulfuric acid of 90% or more, preferably 95% or more, more preferably 98% or more. ml, heat (preferably above 80°C) and dissolve,
Usually 1 hour or more, preferably 2 hours or more, more preferably 8 to 5 hours, 60 to 100°C, preferably 70 to 90°C
React with. After the reaction is completed, the contents are cooled and the precipitated p-sulfonic acid calix [nl arene is separated from F and washed to obtain a compound of R=H, M=H in the formula (I). In addition, when R is a lower alkyl group, p-sulfonic acid calix (nl arene and a suitable alkylating agent, such as an alkyl 10 genide) can be mixed with a solvent that dissolves the alkylating agent, such as water, methanol,
It can be dissolved in ethanol, THF, etc., and an alkyl group can be substituted at the OH site. Further, when R is a lower alkyl carboxylic acid, the lower alkyl carboxylic acid can be substituted at the OH position in the above general formula by using a halogenated alkyl carboxylic acid. Compounds in which M is other than H can be obtained by ion exchange with various ions.

(Effects of the Invention) The uranium adsorbent of the present invention is made of a calixarene derivative represented by the formula (I), has high water solubility, and has a cavity as a host that best forms a coordination compound with the target uranyl ion. Because it can be freely designed and introduced with functional groups, and its skeleton is not as flexible as other cyclic ligands such as crown ether, it exhibits high selectivity for uranyl ions, and other It is characterized by low adsorption of metal ions. Therefore, it has extremely good selectivity and large adsorption power for adsorbing uranium present in seawater. Further, the uranium adsorbent of the present invention is neither highly toxic nor expensive like crown ether. Therefore, if the uranium adsorbent of the present invention is used, uranium in seawater or wastewater can be adsorbed extremely efficiently, and the purity of the adsorbed uranium is high in order to suppress the adsorption of other metals, making it possible to greatly reduce the purification process. This is extremely industrially significant as it can be shortened to .

Hereinafter, the present invention will be explained in more detail by showing examples.

A, Sodium p-sulfonate calix [6] Preparation of allene In a flask equipped with a stirrer and a cooling tube, calix [6J allene 7, 781 was added to 50 ml of 98% concentrated sulfuric acid and heated at 80 °C with stirring. Stirring was continued for an hour.

The end point of the reaction is the point at which no water-insoluble substances are present.

Next, it was cooled to room temperature, the precipitated crystals were separated from P, and 98%
was washed with concentrated sulfuric acid to obtain crystals of p-sulfonic acid calix [61 arene]. The obtained crystals were dissolved in water, neutralized with barium carbonate, and the resulting barium sulfate precipitate was dissolved in F.
Separate. Sodium carbonate is added to the P solution to obtain a sodium p-sulfonate calix[6]arene aqueous solution. Add sodium carbonate until the pH of the solution is 8-9.

After treating the aqueous solution with activated carbon, it is dried under reduced pressure. Dissolve the residue in water and separate the insoluble matter by P. The P solution is treated with activated carbon again, and after removing the activated carbon, the remaining liquid is concentrated. The reaction product obtained by adding ethanol to the concentrated solution and then fractionating and crystallizing it was confirmed to be sodium p-sulfonate calix[6]arene based on the analysis results shown in Table 1 below (Sample 1). ).

In addition, the starting material calix[6]arene is Gutsc
The method of he et al. (C, D, Gutsche et al., J.
Am, Chem.

Soc, 108 8782 (1982))
p-tert-butylcalix obtained by the method [6]
Allene was obtained by debutylation with a dealkylating agent such as klcjh in toluene.

B, Preparation of sodium p-sulfonate calix(6)arene obtained by the method of Example 1 in a flask equipped with a stirrer and a cooling tube. 811 dimethyl sulfoxide to 6°-1 water to 15 d
, 'fe 8.4 Of methi iodide, NaOH 2
．． 85N was heated at 60° C. for 24 hours.

After cooling, the product was precipitated into methanol.

The precipitate was separated from P and dissolved in 10 g/water. After removing the water-insoluble matter by furnace, ethanol was added to the F solution to form a precipitate. This operation was repeated to remove the by-product Nal. The product was confirmed to be sodium 0-methyl-p-sulfonate calix [61 arene] by the analysis shown in Table 1 (Sample 2).

Preparation of C, 0-n-hexyl-p-sulfonate sodium calix [6] arene and 0-n-dodecyl-p-sulfonate sodium calix [6] arene. Instead of methyl iodide, n-hexyl bromide or n
and were obtained in the same manner using -dodecyl bromide.

D, Preparation of sodium 0-carboxymethyl-p-sulfonate calix (6) allene In a flask equipped with a stirrer and a condenser, add 1 part of sodium calix (61 allene) to 0-carboxymethyl-p-sulfonate. f/, NaOH 29. Monobromic acetic acid 8.
69. Add 10gt of water and heat at 80°C for 24 hours.
Made it react.

After the reaction was completed, it was cooled to room temperature, the reaction solution was dried under reduced pressure, and the residue was dissolved in Q, IN, NaOH aqueous solution 11)+/ and heated for 80'04 hours. After drying under reduced pressure, the residue was thoroughly washed with ethanol. The obtained solid is the first
The analysis shown in the table confirmed that it was sodium 0-carboxymethyl-p-sulfonate calix[6]arene (Sample 5).

Table 1 Product analysis results PC: paper chromatography, developing solvent isopropyl alcohol/water = 2/1 (V/V) IR: infrared absorption spectrum, KBr tablet method NMR: '
H-NMR, D20 solution at 20°C However, in sample-8, 150g of Na was used as 15O8H, and measurement was performed at 85°C in D20 solution.

In addition to the analysis in the table above, elemental analysis was also conducted.

For sample-8, elemental analysis was performed using 150 g of Na as 18Q3 (NH4).

Example 1 Each dilute aqueous solution of Sample 1.2.5 was dissolved in Na4 UO2 (CO
8) Add to the dilute aqueous solution of step 8 and add UO2・Calix (
Complex formation of the nl arene derivative was monitored by changes in absorbance in the electronic spectrum at 449 nm. The stability constant of complex formation between each sample and uranyl ions was determined at the point when the change in absorption intensity became strong. This is shown in Table 2. In addition, the values of Comparative Example 1.2 are shown in the figure below.
These are the results of Comparative Example 2 (However, J, Ame, Chem, S
oc, 1025947 (1980) ibid 10
6 2481 Ra-1111 (1984)).

Table 2 Stability Constant for Uranyl Ion Example 2 Samples 1 and 5 used in Example 1 and Comparative Example 1 were tested for selective adsorption of uranium.

This selective adsorption property is determined by adding other metal ions to a solution forming a complex with the uranyl ion of the sample and determining the change in the absorption spectrum of the uranyl ion complex. Table 8 shows the ratio of stability constants (KM) with other metal ions and stability constants (K) with uranyl ions. That is, it can be seen that Sample-5 has the best selectivity to uranyl ions, and Comparative Example 1 has greater interference with other metal ions.

Table 8 K/KM

Claims (1)

[Claims] (1) A uranium adsorbent made of a calixarene derivative represented by the following formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・( I
) However, n: 4 to 10 M: hydrogen, ammonium ion, lower alkyl ammonium ion, metal ion R: hydrogen, lower alkyl group, lower alkyl carboxylic acid or salt thereof, unsaturated alkyl group or aromatic hydrocarbon x, y: hydrogen, alkyl group, aromatic hydrocarbon.